Unpaid people who belong to a parish or religious community and who help welcome the beneficiaries of the Humanitarian Corridors program. Volunteers agree to collaborate with the social workers of the diocesan Caritas unit and with the mentor family to provide all necessary forms of support to the beneficiaries. This may include helping a beneficiary learn Italian, accompanying a beneficiary to public offices, supermarkets, schools, and helping a beneficiary search for job opportunities.

One particular category of volunteers are the so-called "civil service" volunteers: young people under 30 who are participating in the national program of civil service and who have chosen to fulfill their duty by supporting the social workers in the year-long Humanitarian Corridors program at a diocesan Caritas unit.

Vulnerability is the set of conditions determined by physical, social, economic, and environmental factors present in refugee camps that increase the psychological or physical fragility of an individual or family. The protocol establishing Humanitarian Corridors specifically mentioned the following vulnerabilities: the condition of being a single mother with minor children, of being elderly and alone, or of being an unaccompanied minor; plus, having a prior physical or mental handicap, or having suffered sexual or other forms of physical violence or persecution or torture. Under the provisions of the protocol, the beneficiaries of Humanitarian Corridors can be “persons deemed deserving by the UNHCR, at least prima facie, of the recognition of refugee status under the Geneva Convention of 1951 (and its protocol of 1967), but also potential applicants for protection are those living in conditions of objective vulnerability as determined by their personal situation, age, or health conditions.”